Limit Controls
Manual-Reset High Limit
All models are equipped with a manual reset high
limit. Set the manual limit to its maximum set point.
Auto-Reset High Limit
Set the auto limit(s) to 30-40 °F above the desired
operating temperature and 15°F below the Manual
High Limit setting.
Fig. 33: Manual Reset High Limit
Flow Switch
This dual purpose control shuts off the boiler in the
case of a pump failure or low water condition. It is
mounted and wired in series to the main gas valve.
Standard on all models.
NOTE:
Flow switch will not operate if flow is less
than 12 gpm.
Fig. 34: Flow Switch
100% Pilot Safety
All standard boiler models 181-4001 employ electron-
ic devices which close the main gas valve within 8/10
of a second whenever the pilot flame is interrupted.
Pilot flame is automatically lit when the device is pow-
ered. Unit performs its own safety check and opens
the main valve only after the pilot is proven to be lit.
Fig. 35: Safety Control
Fig. 32: 2-Stage Controller
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